Conveyor belts and conveyor systems are well known systems used for the transport of a variety of materials and products. Conveyor belts are designed and used in heavy materials transport such as coal mining and cement manufacturing operations, and in medium and light weight applications such as light materials handling operations, package handling and transport, and the like. For heavyweight applications, it is desirable to provide a belt with high strength, and also one that will resist damage due to impacts with the material being carried, such as where high volumes of hard, sharp or irregular-shaped product are loaded on the belt.
Current high-strength belts are often built from fabrics employing a “straight warp” weave design, in which the warp yarns or cords are not crimped along their lengths but remain substantially straight. Since the tension members in these straight warp weaves do not intertwine with the wefts, they do not help to lock the wefts in place to resist weft pullout when tension is applied to the belt via the conveyor belt fastener lacings.
Further, although the un-crimped arrangement of the warps in straight warp weave designs provide the belt with an extremely high modulus of elasticity in the running direction (the resulting belt will therefore undergo minimal stretch even when subjected to the high tensile loads applied by the conveyor system pulleys), such high strength brings with it high stiffness. This can be a problem where the belt is required to bend around the tight radius of a return-idler or tail-pulley. Thus, to ensure that adequate flexibility, the total number of reinforcing fabric “plies” may be limited to only one or two, which disadvantageously limits the total strength of the resulting belt.
Thus, there is a need for a high-strength conveyor belt carcass design that has enhanced resistance to fastener lacing pullout, and also has increased flexibility as compared to traditional straight warp designs. Such a design should enable the building of conveyor belts with three or more fabric plies to enhance belt strength, while retaining sufficient flexibility to enable the belt to bend around the relatively tight radii of the conveyor system tail pulleys and/or return idlers. The design should have a high stretch resistance, excellent fastener holding strength, and high resistance to tearing, when subjected to high tensile forces imparted by the conveyor system.